﻿using System;
using System.Collections.Generic;
using System.Linq.Expressions;

namespace WPay.Infrastructure.Unity
{
    public class ClassHelper
    {
        /// <summary>
        /// 对象复制(a=>b)
        /// </summary>
        /// <typeparam name="TIn"></typeparam>
        /// <typeparam name="TOut"></typeparam>
        public static class TransExpV2<TIn, TOut>
        {

            private static readonly Func<TIn, TOut> cache = GetFunc();
            private static Func<TIn, TOut> GetFunc()
            {
                ParameterExpression parameterExpression = Expression.Parameter(typeof(TIn), "p");
                List<MemberBinding> memberBindingList = new List<MemberBinding>();
                foreach (var item in typeof(TOut).GetProperties())
                {
                    if (!item.CanWrite)
                        continue;
                    MemberExpression property = Expression.Property(parameterExpression, typeof(TIn).GetProperty(item.Name));
                    MemberBinding memberBinding = Expression.Bind(item, property);
                    memberBindingList.Add(memberBinding);
                }
                MemberInitExpression memberInitExpression = Expression.MemberInit(Expression.New(typeof(TOut)), memberBindingList.ToArray());
                Expression<Func<TIn, TOut>> lambda = Expression.Lambda<Func<TIn, TOut>>(memberInitExpression, new ParameterExpression[] { parameterExpression });

                return lambda.Compile();
            }

            public static TOut Trans(TIn tIn)
            {
                return cache(tIn);
            }

        }
    }
}
